Color filter (CF) is an important component of Liquid Crystal Display (LCD) and a source for LCD producing color. CF layer is formed with photoresist material after a series of lithography processes. Common CF photoresist material is formed by dispersing polymer, monomers, a photo initiator and pigments in a solvent, wherein the pigments are one material for CF practicing color. When light emitted from a backlight module is incident in CF layer, only bands corresponding to R, G and B of the light penetrate CF layer, the other bands of the light are absorbed by the pigments, and thus CF layer produces RGB color after the light passed.
Presently, such the common color photoresist containing the pigments still has a lot of problems needed to be overcome. 1. In aspect of preparation of the materials, because the pigments for common use are insoluble in organic solvents, the pigments are dispersed in the color photoresist material with a dispersing technique to form particles of diameters in 60˜100 nm under action of a dispersant. To the material manufacturers, the dispersing technique and process of the pigments often are the problems difficult to be broken. 2. In aspect of performance of the materials, since the pigments are state of particles dispersed in the material, the pigments inevitably have reflecting and scattering effects on the light, and such effects lead to decline contrast and brightness of LCD. 3. In aspect of fabrication process of the materials, a resolution of the color polymer containing the pigments is subjected to greater restriction and generally difficult to form a shape less than 2 um.
Presently, every major color photoresist manufacturer actively develops color dye materials. The dyes have a more brilliant color, the dye molecules are completely dissolved in solvent, and thus the dyes have a higher penetration than the pigments. If the dyes are used to replace the pigments, the difficulty of dispersing technique and the problem of poor brightness of the pigments can be overcome. However, the dye molecules have poor thermal and light stabilities that restrict the dye for use in color photoresist.